Mai Zen'in

Maki's twin sister, a Kyoto student whose last act arms Maki.

Mai Zen'in is a second-year sorcerer at Kyoto Jujutsu High and Maki's estranged twin sister. Unlike Maki she has a technique, Construction, which forms objects out of Cursed Energy but drains her small reserves.

Quick Facts

School: Kyoto Jujutsu High
Technique: Construction

Facts from the source article.

Background

She mostly fights with a revolver charged with Cursed Energy and keeps her technique hidden to stay one step ahead. After their father fatally wounds her, Mai spends the last of her energy creating a copy of Toji Fushiguro's Split Soul Katana for Maki. That final gift lets Maki destroy the Zen'in clan and remains the last bond between the sisters.